Patients with Idiopathic Hypertrophic Subaortic Stenosis form a subset of patient populations whose anesthesia management is a very difficult problem because little data exists as to the ideal agent or anesthesia technique for their optimal management. There are anecdotal reports of their anesthesia management. We have used Halothane as the sole anesthetic agent in 20 patients and studied how this altered hemodynamics. The data is currently being analyzed.